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We propose to use neural networks to estimate the rates of coherent and incoherent processes in quantum systems from continuous measurement records. In particular, we adapt an image recognition algorithm to recognize the patterns in…

Quantum Physics · Physics 2017-11-15 Eliska Greplova , Christian Kraglund Andersen , Klaus Mølmer

The more information a measurement provides about a quantum system's position statistics, the less information a subsequent measurement can provide about the system's momentum statistics. This information trade-off is embodied in the…

Quantum Physics · Physics 2016-05-16 Gregory A. Howland , James Schneeloch , Daniel J. Lum , John C. Howell

We provide an analytical framework for balanced realization model order reduction of linear control systems which depend on an unknown parameter. Besides recovering known results for the first order corrections, we obtain explicit novel…

Systems and Control · Computer Science 2016-06-24 Carles Batlle , Nestor Roqueiro

Nonlinear interactions are recognized as potential resources for quantum metrology, facilitating parameter estimation precisions that scale as the exponential Heisenberg limit of $2^{-N}$. We explore such nonlinearity and propose an…

Density matrix embedding theory (DMET) is a quantum embedding theory for strongly correlated systems. From a computational perspective, one bottleneck in DMET is the optimization of the correlation potential to achieve self-consistency,…

Chemical Physics · Physics 2019-09-04 Xiaojie Wu , Zhi-Hao Cui , Yu Tong , Michael Lindsey , Garnet Kin-Lic Chan , Lin Lin

We theoretically investigate parameter quantum estimation in quantum chaotic systems. Our analysis is based on an effective description of non-integrable quantum systems in terms of a random matrix Hamiltonian. Based on this approach we…

We study quantum phase transitions by measuring the bond energy, the number density, and the half-chain entanglement entropy in the one-dimensional ionic Hubbard model. By performing the infinite density matrix renormalization group with…

Strongly Correlated Electrons · Physics 2021-02-24 Myung-Hoon Chung

A longstanding problem in quantum metrology is how to extract as much information as possible in realistic scenarios with not only multiple unknown parameters, but also limited measurement data and some degree of prior information. Here we…

Quantum Physics · Physics 2020-03-24 Jesús Rubio , Jacob Dunningham

Quantum phase transitions reveal deep insights into the behavior of many-body quantum systems, but identifying these transitions without well-defined order parameters remains a significant challenge. In this work, we introduce a novel…

We give a causal inference scheme using quantum observations alone for a case with both temporal and spatial correlations: a bipartite quantum system with measurements at two times. The protocol determines compatibility with 5 causal…

Quantum Physics · Physics 2025-04-01 Xiangjing Liu , Yixian Qiu , Oscar Dahlsten , Vlatko Vedral

In this work we apply deep neural networks to find the non-equilibrium steady state solution to correlated open quantum many-body systems. Motivated by the ongoing search to find more powerful representations of (mixed) quantum states, we…

Quantum Physics · Physics 2025-01-13 Johannes Mellak , Enrico Arrigoni , Wolfgang von der Linden

This paper applies the recently axiomatized Optimum Information Principle (minimize the Kullback-Leibler information subject to all relevant information) to nonparametric density estimation, which provides a theoretical foundation as well…

Statistics Theory · Mathematics 2011-03-28 Alexis Akira Toda

We prove a trade-off theorem for order and disorder parameters in one-dimensional quantum spin systems with quenched disorder. For a disordered ensemble with exact Ising symmetry and average translation symmetry, any gapped ensemble must…

Disordered Systems and Neural Networks · Physics 2026-05-29 Jinmin Yi , Chong Wang

We use Abelian Bosonization and density matrix renormalization group method to study the effect of density on quantum phases of long range 1-D Bose-Hubbard model. We predict the existence of supersolid phase and also other quantum phases…

Statistical Mechanics · Physics 2008-12-31 Manoranjan Kumar , Sujit Sarkar , S. Ramasesha

The Schmidt number represents the genuine entanglement dimension of a bipartite quantum state. We derive simple criteria for the Schmidt number of a density matrix in arbitrary local dimensions. They are based on the trace norm of…

Quantum Physics · Physics 2024-12-18 Armin Tavakoli , Simon Morelli

A density matrix describes the statistical state of a quantum system. It is a powerful formalism to represent both the quantum and classical uncertainty of quantum systems and to express different statistical operations such as measurement,…

Machine Learning · Computer Science 2024-05-01 Fabio A. González , Alejandro Gallego , Santiago Toledo-Cortés , Vladimir Vargas-Calderón

Structural quantities such as order parameters and correlation functions are often employed to gain insight into the physical behavior and properties of condensed matter systems. While standard quantities for characterizing structure exist,…

Soft Condensed Matter · Physics 2017-08-23 Aaron S. Keys , Christopher R. Iacovella , Sharon C. Glotzer

The maximum von Neumann entropy principle subject to given constraints of mean values of some physical observables determines the density matrix. Similarly the stationary action principle in the case of time-dependent (dissipative)…

Quantum Physics · Physics 2007-05-23 A. K. Rajagopal , R. W. Rendell

Mean field approach, although a generally reliable tool that captures major short range correlations, often fails in symmetric low dimensional strongly correlated electronic systems like those described by the Hubbard model. In these…

Strongly Correlated Electrons · Physics 2019-09-25 Baruch Rosenstein , Dingping Li , Tianxing Ma , H. C. Kao

The density matrix formalism which is widely used in the theory of measurements, quantum computing, quantum description of chemical and biological systems always imply the averaging over the states of the environment. In practice this is…

Quantum Physics · Physics 2007-05-23 M. V. Altaisky